Hydrogen-containing gas mixtures generally are referred to as synthesis gases, which are employed in various synthesis reactions. Examples include the methanol synthesis, the production of ammonia by the Haber-Bosch process or the Fischer-Tropsch synthesis. Synthesis gases can be produced from solid, liquid or gaseous starting materials.
Processes and apparatuses for producing synthesis gas are known in principle in the prior art. For example, a number of different technical approaches exist, in which liquid or gaseous, carbonaceous fuels with a moderator consisting of steam, carbon dioxide or a mixture thereof are partially oxidized with an oxygen-containing gas. The outlet opening of the used burner is directed into a combustion chamber.
WO 2008/065182 A1 discloses a process for producing synthesis gas, in which a burner is provided with a plurality of nozzle openings, so that a hydrocarbon fuel is guided through the burner separate from an oxidizing gas. The hydrocarbon fuel and the oxidizing gas are separated from each other by a lead-through for a moderator gas. The exit velocity of the moderator gas is greater than the exit velocity of the oxidizing gas.
US 2003/0085385 A1 describes a process in which the reactants hydrocarbon fuel, steam, oxygen and recycled water are guided to the nozzle of a four-stream injector in separate channels. By means of the arrangement, a better conversion of the hydrocarbon fuel should be achieved.
In the process for producing synthesis gas known from WO 95/32148 A, nozzle corrosion should be avoided in that hydrocarbon fuel and oxidant run away from the nozzle in parallel separated by a moderator and there is no mixing of moderator and fuel.
In these known burners at least three outlet openings are present at the burner throat and the atomization of the fuel is effected outside the burner. In the case of an external atomization of the fuel, high relative velocity differences of the reactants exiting adjacent to each other are necessary at the burner throat, in order to perform the necessary atomization work. These high exit velocities of the moderator and/or of the oxidant generate extensive reaction zones. In addition, a high input of energy takes place via the conveying devices (e.g. pumps). Therefore, the nozzle outlet openings must be cooled in particular under transient conditions, such as in start-up and shut-down operations. In the prior art, a great problem also is premature material wear or the removal of material at the burner throat.
In the process for producing synthesis gas by partial oxidation of liquid or gaseous fuels in the presence of oxygen, which is described in DE 101 56 980 B4, the fuel, the oxygen-containing gas and an atomizing medium are separately supplied to the burner, and the atomizing medium is expanded via one or more nozzles directly before the central orifice opening for the fuel. The oxygen-containing gas is guided past the outside of the atomizing nozzle and enters the reactor space concentrically around the mixture of fuel and atomizing medium. This results in exothermal reactions in the vicinity of the burner head, which under transient conditions leads to a great thermal load of the reactor wall in the region of the burner.